Electric-arc lamp.



PATENTED'MAY 12, 1903.

ELECTRIC ARC LAMP. APPLIOATION FILED- snr'r. 16. 1901,

.10 MODEL. H.

Witnesses,

. lnvantor.

174E m5 ",TERS an. PNOTO-LITHQ, WASHINGTON, o. c.

UNITED STATES Iatented May 12, IQO. I

PATENT OFFICE.

ALBERT G. DAVIS, OF SCHENECTADY, NEW YORK, A SSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK;

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 727,596, dated May i2, 1963;;

Application filed September 16, 1901. Serial No. '75 436. (No model.)

' To all whom it may concern:

Be it known that I, ALBERT G. DAVIS, a citizen of the United States, residing at Schenectady, in the county of Schenectady and State s of New York, have invented certain new and useful Improvements in Electric-Arc Lamps,

(Case No. 1,673,) of which the following is a specification.

My present invention relates more esper a cially to the regulation of arc-lamps, and comprises certain improvements described in detail in the following specification, which is to be taken in connection with the accompanying drawings.

I The features of novelty of the invention are particularly pointed out in the appended claims.

In the drawings, Figure 1 is a diagram of circuits useful for explaining the operation of my invention, while Fig. 2 is a representation,

partly in diagram, of an electric lamp em bodying my invention.

The arrangement hereinafter described is intended more particularly for use in connection with alternating current circuits, and

more especially currents of constant potential.

One of the characteristic features of my invention is the provision of means whereby the 0 current in the arc is maintained constant, not

through the regulating action of the carboncontrolling mechanism, but through the interaction of lagging and leading currents flow ingin circuits operatively related to the lamp.

The relation of these circuits to the lamp itself is indicated, perhaps, best in Fig. 1, which illustrates the connections of a plurality of lamps across constant-potential mains. In this figure the lines 1 2 represent constant- 0 potential mains constituting a source of alternating currents. Across these mains is connected for each lamp a circuit for supplying current to an arrangement somewhat similar to a Wheatstone bridge, this arrangement 5 being, however, more commonly known in the art as a monocyclicsquare. Two opposite sides of the square are formed by inductancecoils 3 4, while the two remaining sides 5 6 include, respectively, sources of leading ourrent-such, for example, as condensers. The

condensers may be connected directly in cir cuit or indirectly, if so preferred. By the artifice of inductive connection the same effect may be produced in the present case by one condenser as would be obtained by two it .direct series connection were employed. The inductive connection in the present instance'is such that a single condenser 7, connected in series with two secondary windings 8 9, acts to produce leading currents in the primary windings 5 6 corresponding to these secondaries.

The arc-light terminals 10 11 and the arestriking coil 12 of each lamp are connected across the diagonal of a bridge,'above described, and form what is commonly known as the bridge-circuit.

The inductance-coils 3 4 of the bridge instead of forming separate pieces of apparatus constitute regulating-coils on the lamp-mag- 7o nets, these coils acting in opposition to the arc-striking coil 12.

Fig. 2 illustrates more clearly the arrangement of the arc-regulating coils in the lamp.

In this figure the coils 12 represent the coils of the arc-striking magnet similarly designated in Fig. 1. Acting differentially or in opposition with respect to these arc-striking coils are the regulating-coils 3 4. These coils form opposite sides of the monocyclic square, while the two remaining sides are formed of the primary windings 5 6, shown in the present.

case as inductively related to the same secondary winding 13 across which is connected the condenser 14. This inductive relation between the primary windings and the secondary windingis somewhat preferable to the separate secondary windings 8 9. (Indicated in Fig. 1.) In effect, however, the two arrangements are similar. 0

The arc-striking coils or windings 12 an the electrodes or carbons 1O 11 are connected in series with each other and constitute the bridge-circuit of the monocyclic square. It will be noted that theconductor extending 5 from the main 1 is connected to one end of the coil 4, the other end of which connects with the electrode 11, thereby corresponding to the diagram in Fig. 1, while similarly the same. conductor is also connected to one end of the primary winding 0, the other end of which leads to a terminal of the arc-striking coil 12.

By a suitable proportioning of the condenser effect with respect to theinductance of the regulating-coils 3 4 in the arrangement shown a constant electromotive force supplied by the mains 1 2 will give rise to a constant current in the circuit, including the arc, or, in other words, in the bridge-circuit of the monocyclic square. This is a fact now'well understood in the art and requires no special description, It should be remarked, however, that as the length of the are increases the electromotive force necessary'to maintain constant current in the are likewise increases, the increase in electromotive force of this constant-current or are circuit being accompanied by an increase of current in the sides of the monocyclic square and also in the supply-circuit from the mains 1 2. This fact I take advantage of to secure regulation of the arc. As the arc lengthens, due to the action of the arc-striking coil 12, the currents in the coils 3 a, forming opposite sides of the monocyclic square, increase, thereby opposing the action of the series or arc-striking coil 12 with gradually-increasing force. A point of equilibrium is finally reached at which no further lengthening of the arc takes place. By suitable adjustment this point maybe made to correspond to any desired length or electromotive force of the are, which electromotive force, itis obvious, may be either greater or less than that of the mains 1 2.

With the arrangement thus described the magnitude of the current in the arc is automatically regulated independently of the action of the mechanism for controliingthe arc, thereby securing the stability and smoothness of operation hitherto difficult to obtain in alternating arc-lamps fed from cone stant-potential circuits. The arc-controlling coils 3 4 of the lamp serve to regulate the length of the are by virtue of their action upon the core 15, controlling the upper carbon.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. The combination of constant-potentialv mains, a device for producing constant current through the interaction of lagging and leading currents, carbons or other electrodes connected in series injthe constant-current circuit, and coils forming portions of said device acting to regulate "the length of the are.

2. The combination of a monocyclic square, electrodes of an arc-lamp in the bridge-circuit of said monocyclic square, and an arccontrolling means in circuit. with a side or sides of said square. Z

3. The combination with the electrodes of a'lamp, of aconstant-potential circuit, means for deriving therefrom a constant-current circuit into which latter circuit the said electrodes are connected, and means separate from the constan t-current circuit for controlling the length of the are.

4; The combination with the electrodes of an arc-lamp, of two sets of arc-controlling coils one setor coil being connected in series with the arc and serving to strike the arc and the other set or coil acting in opposition to the first set or coil, means separate from the are for maintaining a constant current through the same, and means for limiting the length of the are. i

5. The combination of a source of current of constant potential, an arc-lamp, and means foining a portion of the mechanism of the lamp for maintaining a constant current in the lamp irrespective of the length of the are.

6. The combination of constant-potential mains, a plurality of lamps fed thereby, and means forming a portion of each lamp mechanism for maintaining a constant current in each lamp regardless of the voltage of the lamp.

7. The combination of constant-potential mains, a device associated therewith for producing constant current, an arc-lamp fed by such constant current, and means forming a portion of said device for regulating the length of the arc.

In witness whereof I have hereunto set my hand this 14th day of September, 1901.

ALBERT G. DAVIS.

Witnesses:

ALEX. F. IVIAODONALD, MARY HELENA SHIEL'os. 

